JPS6117524Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a stylus pressure measuring device for a record player.

Conventional stylus pressure measuring devices, for example, have one end of a leaf spring fixed, the other end open, a record stylus placed on this open end, and the resulting deflection of the leaf spring affixed to the leaf spring. There was one that measured stylus pressure by detecting it with a semiconductor strain gauge and using the amount of electricity output from the semiconductor strain gauge. However, in such conventional examples, ``semiconductor strain gauges are expensive and have poor workability when attached to leaf springs,'' and ``input-output characteristics are linear when stylus pressure is input and electrical quantity is output.'' There were drawbacks such as ``It is not convenient for digitally displaying stylus pressure.''

The present invention is proposed to eliminate such drawbacks, and will be described in detail below with reference to embodiments shown in the drawings.

In the figure, 1 is a base, and the upper surface has a cylindrical portion 1a.
However, there is also a protrusion 1 on the bottom surface for attaching the printed circuit board 2.
b and 1c are formed, respectively. The printed circuit board 2 is fixed to the protrusions 1b and 1c with screws 3. A Hall element 4 is soldered and fixed to the printed circuit board 2 to take out an amount of electricity indicating the stylus pressure. Cylinder part 1
An opening is provided at the upper end of a, and the tip of the needle mounting base 5 inserted into the cylindrical portion 1a is exposed to the outside through this opening. A wire 6 is fixed to the needle mounting table 5, and this wire 6 extends downward. A guide 7 is further inserted into the cylindrical portion 1a, and a wire 6
In addition to serving as a guide, it also serves as a stopper to prevent the needle placement table 5 from lowering more than necessary.

On the underside of the base 1 is a leaf spring 8 that supports the magnet.
It is attached and fixed by a holding plate 9, screws 10, and nuts 11. A boss 1d provided on the bottom surface of the base 1,
1e is a boss for positioning the leaf spring 8. The open end of the leaf spring 8 extends below the cylindrical portion 1a, and the bent portion 6a of the wire 6 is in contact with the open end of the leaf spring 8. That is, the bent portion 6a of the wire 6 is inserted into a pipe portion 8a provided at the open end of the leaf spring 8. A pair of magnets 12 are further attached to the open end of the leaf spring 8.
12 is glued. The pair of magnets 12, 12 are bonded together so that opposing surfaces have opposite polarities.

Now, in the stylus pressure measuring device having the above configuration, if the record stylus attached to the tone arm is placed on the stylus mounting base 5, the leaf spring 8 will be activated in response to the stylus pressure.
is deflected, and the magnets 12, 12 are displaced. That is, the magnetic field applied to the Hall element 4 changes. Therefore, since the Hall voltage output from the Hall element 4 changes in response to the change in the magnetic field, it becomes possible to measure the stylus force using this Hall voltage. For example, the stylus pressure can be digitally displayed by converting the Hall voltage from analog to digital. In this case, it is necessary to determine the distance D and angle A shown in FIG. 4 so that the relationship between stylus pressure and Hall voltage is linear. Also,
It is also possible to make it so that the force (stylus pressure) applied to the leaf spring 8 via the wire 6 is in the vertical direction even when the leaf spring 8 is bent, that is, the wire 6 is always oriented in the vertical direction. This is necessary to obtain a linear relationship. Therefore, in the present invention, as described above, the wire 6 has the needle mounting base 5 fixed to one end.
The other end is bent, and the bent portion 6a is not fixed to the leaf spring 8 but simply abuts on it.

In addition, when the stylus pressure measuring device is attached to the record player 13, the stylus mounting base 5 has a trajectory of the record stylus with a predetermined amount of overhang (as shown by the broken line in Fig. 5).
If it is located above, it becomes possible to simultaneously measure the stylus pressure and adjust the overhang (see Fig. 5).

In addition, when the stylus force measuring device is used independently without being attached to the record player, the structure may be simplified and the record stylus may be placed directly on the open end of the leaf spring.

According to the present invention described above, the strength of the magnetic field applied to the Hall element is changed in response to the difference in the stylus pressure of the record stylus, and the Hall voltage output from the Hall element is changed to an amount indicating the stylus pressure. The structure is extremely simple as it is designed to be used as
Furthermore, since it uses a Hall element, linear input/output characteristics can be obtained over a wide range, and accurate stylus force measurement is possible. Furthermore, by aligning the measurement position with the locus of the record stylus provided with a predetermined overhang, stylus pressure measurement and overhang adjustment can be performed at the same time.

[Brief explanation of the drawing]

The drawings all show the stylus pressure measuring device according to the present invention, and Fig. 1 is an exploded perspective view, Fig. 2 is a front view, Fig. 3 is a bottom view, and Fig. 4 is the relationship between the magnet and the Hall element. FIG. 5 is a diagram showing a device incorporated into a record player. 4 is a Hall element, 5 is a needle mounting table, 6 is a wire, 8
is a leaf spring, and 12 is a magnet.

Claims (1)

[Claims for Utility Model Registration] (1) A magnet, a Hall element placed in a magnetic field formed by the magnet, a stylus mounting base on which a record stylus is placed, and one end fixed and the open end side a plate spring attached to the magnet, and a communication member that associates the needle mounting base and the plate spring, and the plate spring is connected to the plate spring in response to the stylus pressure of the record stylus via the needle mounting base and the communication member. The structure is configured such that the strength of the magnetic field applied to the Hall element is varied in response to the deflection of the spring and the displacement of the magnet, and the Hall voltage output from the Hall element is used as an amount indicating stylus pressure. A stylus pressure measuring device characterized by the following. (2) the communication member is made of wire, one end of the wire is fixed to the needle mounting base;
The stylus force measuring device according to claim 1, which is a registered utility model, characterized in that the other end of the wire is bent, and the bent portion of the wire abuts the open end of the leaf spring. (3) The utility model according to claim 1, wherein the needle mounting base is placed on the upper surface of the cabinet and on the trajectory of the record needle provided with a predetermined amount of overhang. Needle pressure measuring device.